Looks like Tech Autos has accepted the challenge and released a simple but fully functional Google Maps application. The app right just brings down the maps and shows your location, so not too useful. But the developer plans to add Address / point-of-interest search, Directions and Favorites, making the program much more useful.

The bad news: You have to have your phone unlocked/jailbroken as a developer or by using the now defunct ChevronWP7. The latter is more difficult because you actually need a certificate that was hosted on their servers. Luckily XDA has your back on that one.